refactor: report code quality entry tasks per command

`Command.State.codeQualityEntryTasks` accumulated the tasks of all commands of a module and became a `PersistentArray` in #15228 to keep that accumulation linear. It is now per-command state like `messages`: the language processor starts each command with an empty array and reports the command's tasks in the new field `CommandResultSnapshot.codeQualityEntryTasks`, from which `runFrontend` collects them for all commands via the new `Language.Lean.foldCmdSnaps?`.

The `code_quality_log` package test inspected the accumulated tasks from inside a command; it now checks the entries persisted into the `.olean`s instead.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_0147BaiWbHMx3F6dPPkHsXRZ